.left_black_box {
  .head_intro {
    position: absolute;
    top: 0;
    left: 15%;
    width: 50%;
    padding: .08rem .3rem;
    background-color: rgba(255, 255, 255, 0.8);
    box-shadow: 0 0 5px 1px rgba(0, 0, 0, 0.15);
    font-size: .4rem;
    font-weight: 700;
    transform: translateY(-50%);
    transition: all .8s;
  }
}

.unactive {
  .head_intro {
    left: 50%;
    text-align: center;
    transform: translate(-50%, -50%);
  }
}

@media screen and (max-width: 992px) {
  .mobile {
    .left_black_box {
      .head_intro {
        left: 50%;
        text-align: center;
        transform: translate(-50%, -50%);
      }
    }
  }
}